Obstructive sleep apnea is a chronic condition characterized by frequent episodes of upper airway collapse during sleep. Its effect on nocturnal sleep quality and ensuing daytime fatigue and sleepiness are widely acknowledged. Increasingly, obstructive sleep apnea is also being recognized as an independent risk factor for several clinical consequences, including systemic hypertension, cardiovascular disease, stroke, and abnormal glucose metabolism. Estimates of disease prevalence are in the range of 3% to 7%, with certain subgroups of the population bearing higher risk. Factors that increase vulnerability for the disorder include age, male sex, obesity, family history, menopause, craniofacial abnormalities, and certain health behaviors such as cigarette smoking and alcohol use. Despite the numerous advancements in our understanding of the pathogenesis and clinical consequences of the disorder, a majority of those affected remain undiagnosed. Simple queries of the patient or bedpartner for the symptoms and signs of the disorder, namely, loud snoring, observed apneas, and daytime sleepiness, would help identify those in need of further diagnostic evaluation. The primary objective of this article is to review some of the epidemiologic aspects of obstructive sleep apnea in adults.Keywords: obstructive sleep apnea; sleep-disordered breathing; epidemiology Obstructive sleep apnea is being increasingly recognized as an important cause of medical morbidity and mortality. It is a relatively common sleep disorder that is characterized by recurrent episodes of partial or complete collapse of the upper airway during sleep. The ensuing reduction of airflow often leads to acute derangements in gas exchange and recurrent arousals from sleep. The health consequences of obstructive sleep apnea are numerous. If left untreated, it leads to excessive daytime sleepiness, cognitive dysfunction, impaired work performance, and decrements in health-related quality of life. Observational and experimental evidence also suggests that obstructive sleep apnea may contribute to the development of systemic hypertension (1), cardiovascular disease (2), and abnormalities in glucose metabolism (3). Obstructive sleep apnea is insidious and patients are often unaware of the associated symptoms. Cardinal manifestations include loud snoring, witnessed breathing pauses during sleep, fitful sleep quality, and excessive daytime sleepiness. Early recognition and appropriate therapy can ameliorate the neurobehavioral consequences and may also have favorable effects on cardiovascular health (4).Clinical descriptions of obstructive sleep apnea can be found in numerous reports published in the medical literature over the last century (5). However, it was not until the 1980s that the clinical ramifications of disorder became more widely appreciated by the medical community. Although public awareness of obstructive sleep apnea has steadily increased since then, a majority of those affected still remain undiagnosed. Thus, primary care physicians and specialists...

Background-Clinic-based observational studies in men have reported that obstructive sleep apnea is associated with an increased incidence of coronary heart disease. The objective of this study was to assess the relation of obstructive sleep apnea to incident coronary heart disease and heart failure in a general community sample of adult men and women. Methods and Results-A total of 1927 men and 2495 women Ն40 years of age and free of coronary heart disease and heart failure at the time of baseline polysomnography were followed up for a median of 8.7 years in this prospective longitudinal epidemiological study. After adjustment for multiple risk factors, obstructive sleep apnea was a significant predictor of incident coronary heart disease (myocardial infarction, revascularization procedure, or coronary heart disease death) only in men Յ70 years of age (adjusted hazard ratio 1.10 [95% confidence interval 1.00 to 1.21] per 10-unit increase in apnea-hypopnea index [AHI]) but not in older men or in women of any age. Among men 40 to 70 years old, those with AHI Ն30 were 68% more likely to develop coronary heart disease than those with AHI Ͻ5.Obstructive sleep apnea predicted incident heart failure in men but not in women (adjusted hazard ratio 1.13 [95% confidence interval 1.02 to 1.26] per 10-unit increase in AHI). Men with AHI Ն30 were 58% more likely to develop heart failure than those with AHI Ͻ5. Conclusions-Obstructive sleep apnea is associated with an increased risk of incident heart failure in communitydwelling middle-aged and older men; its association with incident coronary heart disease in this sample is equivocal. (Circulation. 2010;122:352-360.)Key Words: epidemiology Ⅲ sleep apnea Ⅲ coronary disease Ⅲ heart failure O bstructive sleep apnea (OSA), characterized by recurrent partial or complete collapse of the upper airway during sleep, is a common chronic condition that affects an estimated 9% of adult women and 24% of adult men. 1 A number of cross-sectional studies have reported an association of OSA with coronary heart disease (CHD), 2-6 although most were small hospital or clinic-based case-control studies that often lacked adjustment for important cardiovascular risk factors. Recent longitudinal studies have found an association of untreated OSA with incident or recurrent cardiovascular disease events. [7][8][9][10] Because untreated OSA generally reflected refusal or voluntary discontinuance of continuous positive airway pressure (CPAP) therapy, a healthy-user effect might be an important source of confounding bias in these studies. Moreover, women were absent from or underrepresented in these studies. Clinical Perspective on p 360Several cross-sectional studies indicate a high prevalence of OSA of 11% to 37% in patients with heart failure. [11][12][13] One study found echocardiographic evidence of left ventricular diastolic dysfunction in 56% of newly diagnosed OSA patients but in only 20% of control subjects; diastolic dysfunction improved with CPAP therapy. 14 Small clinical trials Continuing me...